The planned 250mph service, known as HS2, could cut journey times between London and Birmingham to 50 minutes.

It is proposed to run into a central Birmingham station and a new parkway station near Birmingham Airport.

Business leaders in Birmingham, as well as the city council and MPs, welcomed the announcement. But the £30 billion project has also sparked opposition from residents living close to the proposed route, particularly in areas which may not receive economic benefits.

Some critics have suggested that even Birmingham might not benefit economically.

Mr Fabricant said: “I remain to be convinced that there is an economic case for HS2. But I have an open mind on this.

“In the meantime, I must ensure that any proposed route that goes through my constituency minimises any effect on my constituents.” Other senior Conservatives expressing concerns are Cheryl Gillan, the Welsh Secretary, and David Lidington, the Foreign Office Minister.

And Jeremy Wright, MP for Kenilworth and Southam in Warwickshire, said he would quit as a Government whip if the role prevented him speaking out against the proposals.

But David Cameron, the Prime Minister, made it clear the Government was committed to the policy.

He said: “The most powerful regional policy is transport and the most powerful form of transport is high-speed rail.”